Studies are being conducted studying the behavior, electrophysiology, and anatomy of the pigeon prior to and following sectioning of the primary olfactory nerve. It has been found that the nerve reconstitutes. Pigeons trained to make responses to the onset of olfactory stimulation lose that response when the nerves are sectioned. The response recovers by the end of three months following surgery. If the nerves are sectioned again the response is again lost, indicating the behavior is truly mediated by the olfactory nerves. Electrical recording is also accomplished from a nerve twig from a healed olfactory nerve. The light and electron microscopy also indicate reconstitution. Further studies are being conducted in an attempt to see if more complex olfactory tasks can be learned by operated animals. Completed studies indicate little role of olfaction in the initial part of the reproductive cycle of White Carneaux pigeons. Studies are being continued with feral pigeons and the White Carneaux which have reduced visual input. With a new surgical technique for sectioning the olfactory nerves evidence has been obtained that the nerves reconstitute sooner than indicated by the earlier work.